460 . O, Meyer—Species in the Southern Old-tertiary. 
media Lea sp. have the following cdeoab a0 LL. plicata is com- 
pressed, very inaequilateral; the concentric ribs continue over its 
anterior portion and on this partion cipetie is a radiating furrow. 
more inflated, the beaks are medial, the concentric 
mater. I have a a specimen of it from Claiborne. 
Sete has the inequilateral form of LZ, plicata ; the position of 
e beak however is not quite constant and is sometimes a little 
rae medial. It is inflated like Z. media, but some specimens are 
more compressed. The folds on the surface continue generally 
over the anterior portion, but become less distinct there and some- 
times even vanis slight furrowing of the anterior portion 
may be noticed in ‘most of the specimens, but not in all. In short, 
Leda mater in Jackson stands between L. plicata and L. media ; 
it varies in certain features, and the same features per KS in a 
rate orn the differences between the two species in Clal- 
m these facts the conclusion might be Heatioud) that 
the two eh hiese are also derived from Z. mater 
17 and 18. Astarte sulcata Lea occurs in J ‘ackson with more 
is very singular that the same differences exist between <Astarte 
Nicklini Lea and Astarte parilis C.?,* so that we find two sim!- 
larly looking species of one locality altered in the same nani 
in the other place. 
19. Astarte (Micromeris) parva Lea occurs also in Vicksburg 
in a form which is broader and less ribbed, var. Picken gor 
A a aga from Jackson is more similar to the Claiborne form. 
2. 
DS. I] 
form with estobint lateral margins. These S aatites are 
not constant in Claiborne, and en distinution | is ati made b 
a varietal name, var. Jacksonens 
24. A specimen from Clalwurae resembles Venericardia parv 
Lea, but is very distinct by being still smaller, very much i nflat 
ed, eid a much larger oa and = nodulous ribs. It may be 
call enericardia inflati The same form is also rare in 
J ackson i in a variety with iraiphver Ponto margins, var. Jackson- 
* There exists no description of this species and from the poor figure I can only 
Canes ois determination. 
